This application addresses broad Challenge Area (11) Regenerative Medicine and Specific Challenge Topic 11-DK-103 Organ Innervation. Anatomical and immunohistochemical studies of bladder innervation have identified neural components and some of the neurotransmitter subtypes that are present in late fetal and postnatal development. The association between neural tube defects and bladder dysfunction as well as the neural crest (NC) origin of sympathetic and parasympathetic inputs that innervate the bladder indicates that NC derivatives are essential participants in normal bladder development. Yet, our understanding of how bladder innervation develops and the signaling pathways that control migration of NC-derived progenitors into the bladder are still rudimentary. Moreover, fundamental information about development of innervation associated with the urethral sphincters that control release of urine from the bladder is lacking. Identifying trophic molecules and signaling mechanisms that control migration of NC into the lower urinary tract (LUT) and regulate the differentiation of these progenitors upon arrival is an essential prelude to therapeutic approaches seeking to restore LUT neural components damaged by surgical interventions or innervate tissue-engineered bladder scaffolds in patients. Until recently, isolation of NC-derived cells from the bladder wall to discern their patterns of gene expression was not feasible. Now we have developed unique transgenic lines of mice to enable imaging, isolation and characterization of these multipotent progenitors. As a result we have established the developmental timing and routes of migration taken by neural progenitors that populate the lower urinary tract. Our studies reveal critical transition points in this developmental process at which NC progenitors traffic into the urogenital sinus and then pause in their migration, as if awaiting signaling events that draw them into specific locations. Multiple examples of differential expression between NC populations have been reported that specifically traffic these progenitors into distinct areas of the developing embryo. It is possible that signaling molecules essential to development of other aspects of the peripheral nervous system may also play a role in development of innervation in the LUT. However it is already well known that axial level along the neural tube is a major factor in determining the migratory properties, developmental potential and ability of NC-derived lineages to colonize different regions of the embryo. Thus, it is highly likely that sacral NC progenitors that populate the LUT and give rise to pelvic ganglia and neural components of the bladder and urethra express a unique complement of receptors and signaling molecules that guide the phases of their migration. We propose to capture NC-derived progenitors at discrete transition points during their migration into the LUT and define their gene expression profiles. This approach will circumvent the technical challenge of the scarcity and dispersed distribution of NC-derived progenitors within tissues has previously hampered efforts to identify their gene expression signatures within organs. Comparative bioinformatics between NC cell populations isolated from distinct transition phases during LUT innervation will rapidly identify signaling pathways that participate in development of the resulting neural components. To provide temporal and spatial information relevant to LUT innervation we will generate in situ hybridizations of candidate genes that are likely effectors of LUT innervation based on their roles in other aspects of peripheral nervous system development. Gene expression patterns derived by in situ hybridization will complement the microarray work and identify key trophic factors and guidance molecules during the critical stages when NC progenitors traffic into the LUT. Our overall goal is to establish a gene expression resource that will provide rational for clinical efforts to restore function to damaged pelvic neural elements or tissue- engineered bladder substitutes. The proposed studies will generate a comprehensive resource of gene expression patterns that can be mined by investigators interested in urogenital tract development and disease. Our efforts will propel the field of LUT innervation development forward and make a significant impact on biomedical research that seeks to restore bladder innervation across a range of clinical settings, from pediatric patients with spina bifida to patients suffering pelvic neural damage secondary to surgical manipulations. PUBLIC HEALTH RELEVANCE: The studies proposed aim to identify essential genes that control development of nerves in the lower urinary tract that regulate bladder control and sexual function. These studies are important for understanding how these nerves normally develop and for deriving technologies that will restore neural function in urogenital birth defects or after pelvic surgery. This proposal is in response to the broad Challenge grant area of Regenerative medicine and meets multiple needs for basic research in development lower urinary tract innervation.